#3269 The effects of self-performed dietary sodium reduction on blood pressure and the renin-angiotensin-aldosterone system

Résumé fourni par la source

Abstract Background and Aims Lifestyle factors as contributors to cardiovascular disease has been the focus of attention in recent years. Dietary sodium intake is a known risk factor to high blood pressure (BP) and thus cardiovascular disease. Several studies have shown a blood pressure decreasing effect of reducing dietary sodium however only few of these studies examined self-performed sodium reduction. Instead, they used hand-out low-sodium diets and results from these are therefore sparsely transferable to a real-life setting. Additionally, knowledge on the underlying physiology of the BP response is still lacking. This study aimed to test the effects of a self-performed dietary sodium reduction on BP in patients with essential hypertension and examine the effects on the renin-angiotensin-aldosterone system. Method A randomised, non-blinded clinical trial including 72 patients with hypertension was conducted. Participants were randomized 2:1 to either self-performed sodium reduction or a control group for a study period of four weeks. Both oral and written advice on lowering sodium intake was provided to the intervention group. Blood samples, 24-hour urine collection and 24-hour ambulatory BP measurements were performed before and after the intervention. Results Urinary 24-hour sodium excretion decreased 66 mmol (95% CI −96; −37 mmol) in the intervention group compared to the control group, which attained no significant change (5 mmol, 95% CI −12; 21 mmol). Systolic 24-hour BP decreased 9 mmHg after low-sodium diet compared to the control group (95% CI −13; −4 mmHg). Similarly, the difference in reduction in diastolic BP between the groups was 5 mmHg (95% CI −8; −1 mmHg) Plasma levels of renin increased significantly in the intervention group compared to the control group (median change 6.8 pg/ml vs. 0.0 pg/ml, P < 0.0005). Likewise, did we find an increase in plasma aldosterone in the intervention group with a mean difference of 37.68 pg/ml compared to the control group (95% CI 17.34; 58.01, P = 0.0004) An association between change in aldosterone levels and change in BP was found (P = 0.005), however we did not find this association for renin and BP. Neither changes in renin nor aldosterone were associated to the reduction in sodium excretion. Conclusion A self-performed dietary sodium reduction of 66 mmol/day led to a decrease in 24-hour BP of 9/5 mmHg compared to a control group. Plasma renin and plasma aldosterone levels increased significantly compared to a control group, likely as a compensatory mechanism. The change in BP was related to the change in plasma aldosterone. Advice on how to lower sodium intake as part of treatment of patients with essential hypertension could lead to better blood pressure control and thus lower risk of cardiovascular disease.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.